Why do robins discard their young?

Robins may discard their young for several reasons, primarily related to survival and health. If a nestling is weak, sick, or not thriving, the parents may instinctively remove it to conserve resources for the healthier siblings. Additionally, environmental stressors, such as a lack of food or threats from predators, can lead to such behavior as a means of ensuring the overall survival of the remaining chicks. This is a natural instinct aimed at maximizing the chances of survival for the stronger offspring.